How To: Use iPhone 4 data plan with iPad 3G

I love my iPad 3G, almost unnecessarily so. I use it as my primary computer for a multitude of tasks. The only thing that I dislike about my iPad is that I have to pay AT&T even more money to use their data network, even though I'm already paying for it with my new iPhone 4.

We have covered in the past how to manage your 3G data with your iPad using the Apple/AT&T-sanctioned methods built in to the device itself. Today, we want to show you how you can swap Micro-SIMs to make use of your iPhone's unlimited data plan with your iPad.

Note: This is not an officially sanctioned technique and you do this at your own risk! If AT&T comes down on your SIM-swapping antics with the force of a truckload of anvils... you are on your own, brother.

That said, let's proceed.

For those of you that happen to have both an iPhone 4 and an iPad 3G, maybe you aren't too concerned about paying AT&T twice for something you will rarely use simultaneously. In my case, I wanted to see if it was even possible in spite of Apple saying otherwise.

Both the iPhone 4 and iPad 3G use a similar 3ff micro-SIM, so the swap seemed easy enough. The iPhone did not include a SIM-removal tool for this iteration; handily, though, the iPad included one. I set to work using the included tool to remove the tiny trays and lay out my SIM cards. Be careful when doing this not to mix up the trays and SIM cards. While the cards themselves are similar, the trays are actually mirror images of one another.

I placed the iPhone's micro-SIM in the tray for the iPad and loaded the combination into the iPad. Then, using the Settings app, I re-enabled cellular data. Without much ado, the iPad found a 3G signal and was connected. I went to Safari to try out my newly-found freedom only to discover something was amiss -- the pages were not loading.

Worried all was lost, I restored the SIM cards to their original devices and went about my business. Later, inspiration struck in the form of a well-written post over at Engadget about hacking your SIM cards. It covered physically hacking a standard SIM down to size so that it could be used as a micro-SIM as well as the requisite APN settings for each carrier and device -- jackpot!

[If you're trying to go the other way, from Micro-SIM to SIM, we covered this adapter option recently. –Ed.]

I repeated the same procedure as before; however this time, prior to enabling cellular data, I made a change to my iPad's APN settings. The APN settings are like the login credentials for the data network. In many cases they are detected over-the-air, but this time they were not.

Here are the APN settings that are required:

• APN name: wap.cingular

• username: WAP@CINGULARGPRS.COM

• password: CINGULAR1

After changing the APN settings and enabling cellular data I again used Safari to test out my internet connection. It stuttered at first and I thought I had failed, but soon the connection picked up and I was browsing the web over 3G. It was very exciting to use my iPad over 3G for the first time all without having to pay for an additional data plan.

The settings are not static, so once you swap the SIM cards back, the iPad will revert to its default configuration. Since there are several tiny parts involved, this is probably not something you would want to attempt on a subway or while in the airport. However, if you're in a pinch and really don't want to pay AT&T twice, this is a workable alternative.